CHICAGO, Dec 18 (Reuters) -Spot basis bids for soybeans delivered by barge to U.S. Gulf Coast terminals were slightly higher on Wednesday on demand hopes, even as Chicago soybean futures plunged to a four-year low, traders said.

* Gulf barge loadings for corn were steady.

* Chicago Board of Trade soybean futures Sv1 faced heavy pressure from bumper crop prospects in Brazil and a slide in soyoil prices, amid a lack of biodiesel support in a tentative U.S. Congressional stopgap funding bill, traders said.

* The U.S. Department of Agriculture on Wednesday confirmed private sales of 120,000 metric tons of U.S. soybean cake and meal for delivery to Colombia during the 2024/25 marketing year.

* USDA also confirmed private sales of 135,000 metric tons of U.S. corn for delivery to Colombia during the 2024/25 marketing year.

* At the Gulf, CIF soybean barges loaded in December traded at 92 and 95 cents over Chicago Board of Trade January SF25 soybean futures, traders said.

* Barges loaded in split-January also traded at 92 cents over futures, while those loaded in January traded at 93 cents over futures.

* And barges loaded in split-February traded at 86 cents over March SH25 soybean futures, and those loaded in February traded at 84 cents over March futures.

* CIF soybean Gulf barges loaded in December were bid at 92 cents over Chicago Board of Trade January SF25 futures, up 1 cent from Tuesday.

* FOB export premiums for January soybean shipments were 1 cent lower at about 108 cents over futures.

* For corn, CIF barges loaded in April-May traded at 61 cents over CBOT May corn futures CK25, while barges loaded in June-July traded at 61 cents over July corn futures CN25.

* CIF corn barges loaded in December were bid steady at 69 cents over CBOT March corn CH25 futures; January corn barges were bid at 71 cents over March futures, also steady.

* FOB offers for corn shipped from the Gulf in January held steady at nearly 87 cents over CBOT March futures, though offers for deferred months turned lower.

Reporting by P.J. Huffstutter; Editing by Shreya Biswas

For displays of CIF basis, click on the codes in brackets: U.S. CIF Gulf soybeans GRYM U.S. CIF Gulf corn GRYN U.S. CIF Gulf SRW wheat GRYO U.S. CIF Gulf HRW wheat GRYP
For displays of FOB basis, please click on the following codes in brackets: U.S. FOB Gulf corn GRZC U.S. FOB Gulf soybeans GRZD U.S. FOB Gulf SRW wheat GRZE U.S. FOB Gulf HRW wheat GRZF LINKS Corn prices page: cpurl://apps.cp./cms/?pageid=corn-cash-market
Wheat prices page: cpurl://apps.cp./cms/?pageid=wheat-cash-market
U.S. barge freight BG/US
U.S. export sales estimates USDA/EST
U.S. grain export summary GRA/U
Brazil soybean export prices SYBS
Brazil corn export prices SYBX
Argentina grain prices GRA/ARG
Russia grain prices GRA/RU